Slot tube swirler injector

ABSTRACT

An injector assembly has a liquid propellant manifold body on which there are located a plurality of holes of approximately the same depth, first passageways are connected to said holes between the top and the bottom of said holes and second passageways are connected to the bottom of said holes. A slot tube swirler injector or element is inserted and fixed in place in each hole. Each of these swirler elements has two sets of openings for inducing a swirling action along its length, one set of said openings is adjacent the bottom of the element and opens into one of said second passageways and the sec second set of openings opens into one of said first passageways. An injector face plate for gaseous propellant distribution is fixedly spaced a predetermined distance from said manifold body. Said face plate has openings therein and said elements extend into said openings. The openings are spaced from said elements to permit a flow of gas therearound. A first manifold directs a primary liquid flow to said first passageways and a second manifold directs a secondary liquid flow to said second passageways. Control means are provided to give desired primary and secondary flows. A combustion chamber is fixed around the face plate of said injector head and terminates in a nozzle rearwardly thereof. Means are provided for directing a gas to the forward side of said injection means. An opening or openings are provided to permit the gas to be admitted between the manifold body and face plate. In one instance, a cylindrical passageway means is used and in another the injector head is formed having radial spraybars with the openings being located therebetween. In the event throttling is not desired, one set of slots can be used.

United States Patent [72] Inventor Carl L. C. Kah,.lr.

Palm Beach Gardens, Fla. [2|] Appl. No. 725,954 [22] Filed May 1,1968[45] Patented June 1, I971 [73] Assignee United Aircraft CorporationEast Hartford, Conn.

[54] SLOT TUBE SWIRLER INJECTOR 18 Claims, 8 Drawing Fig 1 60/39.74 [51]F02g 1/00 [50] 60/3974,

[56] References Cited UNITED STATES PATENTS 2,603,535 7/1952 Ipsen et al239/404 2,701,164 2/1955 Purchas, Jr. et al 239/404 Primary Examiner-Samuel Feinberg Attorney-Jack N. McCarthy XIiS'II ACTaAn injectorassemblyhas a liquid propellant manifold body on which there are locateda plurality of holes of approximately the same depth, first passagewaysare connected to said holes between the top and the bottom of said holesand second passageways are connected to the bottom of said holes. A slottube swirler injector or element is inserted and fixed in place in eachhole. Each of these swirler elements has two sets of openings forinducing a swirling action along its length, one set of said openings isadjacent the bottom of the element and opens into one of said secondpassageways and the sec second set of openings opens into one of saidfirst passageways. An injector face plate for gaseous propellant distribution is fixedly spaced a predetermined distance from said manifoldbody. Said face plate has openings therein and said elements extend intosaid openings. The openings are spaced from said elements to permit aflow of gas therearound. A first manifold directs a primary liquid flowto said first passageways and a second manifold directs a secondaryliquid flow to said second passageways. Control means are provided togive desired primary and secondary flows. A combustion chamber is fixedaround the face plate of said injector head and terminates in a nozzlerearwardly thereof. Means are provided for directing a gas to theforward side of said injection means. An opening or openings areprovided to permit the gas to be admitted between the manifold body andface plate. In one instance, a cylindrical passageway means is used andin another the injector head is formed having radial spraybars with theopenings being located therebetween. In the event throttling is notdesired, one set ofslots can be used.

PATENTED JUN 1 1911 SHEET 3 OF 3 SLOT TUBE SWLER INJECTOR The inventionherein described was made in the course of or under a contract with theDepartment of the Air Force.

BACKGROUND OF THE INVENTION This invention relates to means foratomizing a liquid which is to be mixed with a gas and particularly toan injector assembly in which two propellants are to be used wherein oneis a liquid and the other is a gas. In the prior art, various types ofinjectors and atomizing nozzles have been used. However, no suchinjector element is known which will provide the same degree ofatomization for a given flow and area with the mechanical simplicity anddurability such as the means described herein. While dual orifice typenozzles are known, the construction has been different and complicatedas shown by US. Pat. No. 2,703,260. Other type injectors which have goodatomization require that streams of liquid impinge on each other asshown by U.S. Pat. No. 3,122,885.

SUMMARY OF INVENTION A primary object of the present invention is toprovide for good atomization in an injection device over a throttlingrange by a momentum exchange between a primary flow and secondary flowachieved by a direct swirling action within a tube element.

In accordance with another aspect of the present invention, an elementis provided which is without moving parts and is a member which is fixedto the injector.

In accordance with a further aspect of the present invention, aninjection element comprises a tube of small constant diameter withtangential inlet slots. A second set of tangential openings of differentarea is provided at a different position along the elements length andseparately manifolded for throttling. This configuration of element hasbeen proven to provide an unusually fine atomization (relative to othercomparable size elements and flow rates per element) even with verysmall tube diameters and long element lengths.

This inventionprovides for an injection device which will give anexcellent degree of atomization which is inexpensive to fabricate,uncomplicated, and very durable. Adjacent elements can have oppositeswirl movements directed therethrough if desired. This invention throughthe use of swirling liquid momentum interchange between the flow througha first set of slots and low pressure differential throttled flowthrough a second set of slots provides a stable highly atomizedinjection pattern over a wide range of flows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is an enlarged view showing oneof the swirler elements.

FIG. 5 is a view taken through the line 5-5 of FIG. 4 showing thepositioning of one set of slots in the swirler element.

FIG. 6 is an enlarged view showing an end view of two swirler elements.

FIG. 7 is an end view of four swirler elements showing alternateelements having opposite swirl movement.

FIG. 8 is a modification of the invention showing elements having oneset of slots.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, arocket 2 is shown having a combustion chamber 4 enclosed by acylindrical wall 5 with injection means 6 forming one end of thechamber. At the other end of the combustion chamber the wall 5 is formedas a nozzle (not shown). The injection means 6 is located at the centerof a main body 8. The outer portion of the main body 8 surrounding theinjection means is fixed to the forward part of the rocket by bolts 10which extend through a flange l2 positioned around the wall 5 of therocket and which is in contact with the main body.

The part of the center of the main body 8 forming part of the injectionmeans 6 and facing the chamber 4 is shaped as a conical portion 14 whichtapers inwardly from its outer edge, which is substantially the samedimension as the inner dimension of the combustion chamber 4, to a pointadjacent the center of the main body 8. A passageway 16 extends from thefront of the main body 8 to the center of the conical portion 14 for apurpose to be hereinafter described.

A conically shaped plate member 18, having the same cone angle as theconical portion 14 is spaced from said conical portion 14 apredetermined distance rearwardly by a spacer member 20. Plate member 18has face supporting rib sections 21. Spacer member 20 is fixed to theouter edge of the plate member 18. This plate member 18 can be formed ofa porous material to provide for cooling of the face of the injectorhead. The spacer member 20 is held against the outer edge of the conicalportion 14 by a flange 22 extending from a washer 24. This washer 24 ispositioned in a recess 26 formed between the main body 8 and forward endof the wall 5 of the rocket. These parts are sized so that when thebolts 10 are torqued into place and the main body 8 and wall 5 are inproper mating engagement, spacer member 20 and washer 24 become fixedlypositioned. Ring 22 may be separately bolted into position.

The part of the center of the main body 8 forming part of the injectionmeans 6 can be formed as inwardly extending radial spraybars 30 withradial passageways being located between each pair of adjacentspraybars. These will serve the same purpose as the passageway 16referred to above. The rear part of the spraybars could be slantedforwardly as they extend inwardly to produce the conical line as shownin FIG. 1.

Whether or not the center of the main body is formed with a passageway16 or formed having spraybars 30, the plate member 18 forming the faceof the injector would appear as it does in FIG. 2. As shown in FIG. 2,radial slots appear around the surface of plate member 18, long slots 32and short slots 34, the length of the slots being different to providefor proper distribution over the circular face. In the main body 8 inline with each of the slots 32 and 34 are holes 40 extending in a linefor substantially the length of the slot. Naturally, when thespraybar-type construction is used, the holes 40 extend down therearward face of each spraybar, one of which is aligned behind each slot32 and 34.

Around the outer periphery of the main body 8 two manifolds are located,a primary liquid manifold 50 and a secondary liquid manifold 52. Theprimary manifold 50 is formed by a groove 54 around the periphery of themain body 2 and a mating groove 56 which is formed in a cover member 58which is fixed to the main body 3. The secondary manifold 52 is formedby a groove 60 around the periphery of the main body 8 and a matinggroove 62 which is formed in a cover member 64 which is fixed to themain body 3. These covers 58 and 64 can be fixed by any desirable means.

In radial alignment in the main body with each of the slots in the faceof the injector head and the lines of holes 410 in the center of themain body are two passageways 7 0 and 72. These passageways and 72 areformed by being drilled from the outer periphery of main body 8 ingroove 60. Passageway 70 intersects the bottom of each line of holes 40which are aligned behind a single slot 32 or 34. Passageway 72intersects each line of holes midway between the passageway 70 and theface of the injector head.

In each of the holes 40 a swirler element MN) is fixed to connect thepassageways 7t) and 72 to the face of the injector.

Each swirler element is fixed in place by brazing or any other meanswhich will provide a seal between each element and the portions of thehole 40 which it engages. This is done to prevent leakage betweenpassageways 72 and 70 and between passageway 72 and the rear opening ofthe holes 40.

Each swirler element 100 comprises a tube having two sets of slots 102and 104 which cooperate respectively with passageways 72 and 70. Eachslot of each set of slots is shown being tangentially positioned toprovide a swirling effect within the element. The tangential entryforces the liquid from either primary manifold 50 or secondary manifold52 to swirl inside the cylindrical swirler element 100 and provide aselfatomized, hollow spray cone. In the construction shown, there arethree slots in each set. The rearward end of each swirler element ispositioned approximately at the face of the surface 14. One exception isthe elements adjacent the wall of the combustion chamber where the outersides are lengthened so as to control burning adjacent the face of thewall.

Since the slots 104 are used to inject the liquid from the secondarymanifold 52, the passageways 70 serve this purpose as drilled; however,since the slots 102 are used to inject the liquid from the primarymanifold 50 a connecting passageway 74 is drilled from groove 54 to eachpassageway 72 and a plug 81 is placed at the end of each passageway 72between the intersection of passageway 74 and the groove 60. It can beseen that a liquid entering the manifold 50 will pass throughpassageways 74 and 72 and into slots 102 t be discharged from the freeend of element 100. A liquid entering the manifold 52 will pass throughpassageways 70 and enter slots 104 to be discharged from the free end ofelement 100. To provide for a maximum desired flow to the secondaryslots 104, two additional passageways 96 and Q8 are placed in radialalignment in front of the two'passageways 70 and 72. Holes 110 connecteach passageway 96 to its adjacent passageway 70 and holes 112 connecteach passageway 98 to its adjacent passageway 96. Adjustment of holes110 can be used to control the distribution of propellant across theface of the injector. Passageways 96 and 98 intersect groove 60 in thesame manner as passageway 70. It can be seen, therefore, thatpassageways 96 and 98 are fed from the secondary manifold 52 in the samemanner as passageway 70.

A primary liquid propellant supply 82 is shown connected to an inlet 90of manifold 50 by conduit means having a control valve 86 and asecondary liquid propellant supply 80 is shown connected to an inlet 92of manifold 52 by conduit means having a control valve 84. While thesupply arrangement has been shown, a single liquid supply can be usedwith a divider valve to control the flow between the primary andsecondary manifolds.

When only one liquid manifold is used and deep throttling is notdesired, a swirler element can be used having one set of slots. Anarrangement of this type is shown in FIG. 8. The tube elements 100A havea single set of tangential openings 104A. Passageways 70A and 96A leadto said openings 104A. Passageway 110 interconnect these passageways andpassageways 112 interconnect passageways 96A and 93A.

The passageway 16 formed in the main body 8 as shown in FIG. 1, or theradial passageways located between the spraybars 30 as shown in FIG. 3,have a gas directed thereto to be admitted to the openings 32 and 34 inthe plate member 18. The gas is directed to the space between theconical portion 14 and plate member 18 of the injection means by aconduit means 120 from a chamber 122 formed with the forward part of theinjection means. The conduit means 120 is fixed to the forward part ofthe main body 8 by a flange 124 which is fixed thereto by bolts 126. Thespacing between elements 100 and between the main body 8 and face plate18 was selected to provide gas injection completely surrounding eachelement and to create a uniform mixture ratio profile along the lines ofelements 100.

The spacing of the tube elements 100 can be constructed such as shown inFIG. 6 to provide a uniform injected propellant mixture ratio along arow of elements where the elements are round and placed in a long slot.In this arrangement, the area A, is made equal to two times the area AThese areas are determined by placing a circle around each of theadjacent elements 100, using the center of the element as the center ofthe circle, the diameter of the circle being equal to the width of theslot in which the element is located. When this is done, it can be seenfrom FIG. 6 that an area A, is formed by the overlapping of adjacentcircles, and two areas A, are formed between the edge of the slot andthe outer edge of the two circles.

As stated hereinbefore, the swirl of the liquid injected through thetube of an element is created by injecting the liquid into the tubethrough tangential slots. Primary and secondary slots are used to allowthrottling. The primary slots are located closest to the tube exit sothat the swirl velocity of the primary liquid has minimum tube wallfriction dissipation prior to being injected into a chamber downstreamof the open end of the element 100. The primary slots are sized to giveacceptable atomization at low throttle. When the secondary liquid supplyis throttled there is a momentum interchange between the secondary flowand the higher velocity primary flow, this provides a suitable liquidinjection velocity for good performance. The swirling of the liquidsinjected through the tube also provides for regenerative cooling of thetube and dissipation of the heat input from the end exposed to thecombustion chamber. In the arrangement of elements the direction ofswirl can be different in different elements, that is some can be madeso that the slots impart a clockwise swirl while others can be made toimpart a counterclockwise swirl. In one injection assembly tested theelements were installed so that in a line, adjacent elements hadopposite swirls (see FIG. 7). The counter rotation of the spray conesenhances mixing by producing a more uniform atomization pattern along aline of elements.

In an element having one set of slots of a width W, and a tube having adiameter D, it was found that the ratio of W/D should be less than 0.25for the best results. Swirler elements have been tested having tubediameters as small as 0.075 inches and with L/D ratios as high as from 7to 25 with satisfactory results. An element having the slot area equalto one-halfof the tube area gave excellent results.

If temperatures within the combustion chamber 4 are such that the platemember 18 and spacer member 20 will experience varying degrees ofgrowth, the flange 22 can be made to extend inwardly further and coverthe outer circumference of the plate member 18. Spacing of the parts canthen be made such that thermal growth of the plate would be permittedwithout interfering with any movement of the spacer member 20. The platemember 18 can be fixed against rotation by any means desired, such as apin and slot, so that the plate slots 32 and 34 and aligned elementstherein will maintain a proper relationship during thermal growth of theparts. I claim:

1. Injection means for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, a tube element for atomizing the liquid propellant, said tubeelement having a constant inner diameter, said tube element having anopen end and a closed end, said tube element having an opening thereinalong its length, said opening being located adjacent the closed end ofthe tube element, said opening being located at an angle to the radiusof the tube element to provide a swirling effect, the open end of saidswirler tube element opening into said combustion chamber, means fordirecting a liquid propellant flow to said opening of the tube elementfor injection into said combustion chamber, and means for directing agas propellant flow into said combustion chamber to mix with saidatomized liquid propellant injected through said tube element, said tubeelement having an L/D ratio in the range of 7-25.

2. An injector assembly for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, said injector assembly having a body on which there are located aplurality of holes, a tube element being positioned in each hole, saidtube element having an open end and a closed end, each of said tubeelements having a first opening therein along its length, said firstopening being located adjacent the closed end of the tube element, saidfirst opening being located at an angle to the radius of the tubeelement to provide a swirling effect, a face plate spaced from saidbody, said face plate having second openings therein, said tube elementsextending into said second openings, said second openings being spacedfrom said tube elements to permit a flow of gas therearound, means fordirecting a liquid propellant flow to said first opening of the tubeelements, means for directing a gas propellant flow between said bodyand said face plate so that it can pass around said tube elements insaid second openings.

3. A combination as set forth in claim 2 wherein said second opening isa slot and each slot contains at least two tube elements.

4. A combination as set forth in claim 3 wherein adjacent tube elementshave their first openings directed in opposite directions to provide aclockwise swirling motion in one element and a counterclockwise swirlingmotion in the other.

5. A combination as set forth in claim 2 wherein the tube elements areof constant diameter.

6. A combination as set forth in claim 2 wherein the first opening alongthe length of a tube element has an area less than the area of the openend of the tube element.

7. A combination as set forth in claim 2 wherein the width of the firstopening along the length of a tube element is less than one-quarter ofthe diameter of the tube element.

8. A combination as set forth in claim 2 wherein the tube elements havean L/D ratio in the range of 7 to 25.

9. A combination as set forth in claim 2 wherein said body includesradially disposed spray bars with each spray bar having a plurality ofholes located along its length, and said means for directing a gaspropellant flow directs said flow between said spray bars to a positionbetween said body and said face plate.

10. An injector assembly for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, said injector assembly having a body on which there are located aplurality of holes, a tube element being positioned in each hole, saidtube element having an open end and a closed end, each of said tubeelements having two openings therein along its length, one of saidopenings being located adjacent the closed end of the tube element, saidone opening being located at an angle to the radius of the tube elementto provide a swirling effect, the second of said openings being locatedbetween said one opening and the open end of the tube element, saidsecond opening being located at an angle to the radius of the tubeelement to provide a swirling effect, a face plate spaced from saidbody, said face plate having third openings therein, said tube elementsextending into said third openings, said third openings being spacedfrom said tube elements to permit a flow of gas therearound, means fordirecting a primary liquid flow to said second opening of the tubeelements, means for directing a secondary liquid flow to said oneopening of the tube elements, and means for directing a gas flow betweensaid body and said face plate so that it can pass around said tubeelements in said third openings.

11. A combination as set forth in claim 10 wherein said second openingis a slot and each slot contains at least two tube elements.

12. A combination as set forth in claim 11 wherein adjacent tubeelements have their first openings directed in opposite directions toprovide a clockwise swirling motion in one element and acounterclockwise swirling motion in the other.

13. A combination as set forth in claim 10 wherein the first openingalong the length of a tube element has an area less than the area of theopen end of the tube element.

14. A combination as set forth in claim 10 wherein the width of thefirst opening along the length of a tube element is less thanone-quarter of the diameter of the tube element.

15. A combination as set forth in claim 10 wherein the tube elements areof constant diameter.

16. A combination as set forth in claim 10 wherein the tube elementshave an L/D ratio in the range of 7 to 25.

17. A combination as set forth in claim 10 wherein the adjacent tubeelements are spaced apart and from their cooperating third opening bythe relationship A,=2A where A, and A, are the areas as shown in FIG. 6.

18. An injector assembly for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, said injector assembly having a body, said body having radiallydisposed spray bars, each spray bar having a plurality of holes locatedalong its length, a tube element being positioned in each hole, saidtube having an open end and a closed end, each of said tube elementshaving two openings therein along its length, one of said openings beinglocated adjacent the closed end of the tube element, said one openingbeing located at an angle to the radius of the tube element to provide aswirling effect, the second of said openings being located between saidone opening and the open end of the tube element, said second openingbeing located at an angle to the radius of the tube element to provide aswirling effect, a face plate spaced from said body, said face platehaving third openings therein, said tube elements extending into saidthird openings, said third openings being spaced from said tube elementsto permit a flow of gas therearound, means for directing a primaryliquid flow through said spray bars to said second opening of the tubeelements, means for directing a secondary liquid flow through said spraybars to said one opening of the tube elements, and means for directing agas flow between said spray bars to said face plate so that it can passaround said tube elements in said third openings.

1. Injection means for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, a tube element for atomizing the liquid propellant, said tubeelement having a constant inner diameter, said tube element having anopen end and a closed end, said tube element having an opening thereinalong its length, said opening being located adjacent the closed end ofthe tube element, said opening being located at an angle to the radiusof the tube element to provide a swirling effect, the open end of saidswirler tube element opening into said combustion chamber, means fordirecting a liquid propellant flow to said opening of the tube elementfor injection into said combustion chamber, and means for directing agas propellant flow into said combustion chamber to mix with saidatomized liquid propellant injected through said tube element, said tubeelement having an L/D ratio in the range of 7-25.
 2. An injectorassembly for injecting two propellants into a combustion chamber, onepropellant being a liquid, the other propellant being a gas, saidinjector assembly having a body on which there are located a pluralityof holes, a tube element being positioned in each hole, said tubeelement having an open end and a closed end, each of said tube elementshaving a first opening therein along its length, said first openingbeing located adjacent the closed end of the tube element, said firstopening being located at an angle to the radius of the tube element toprovide a swirling effect, a face plate spaced from said body, said faceplate having second openings therein, said tube elements extending intosaid second openings, said second openings being spaced from said tubeelements to permit a flow of gas therearound, means for directing aliquid propellant flow to said first opening of the tube elements, meansfor directing a gas propellant flow between said body and said faceplate so that it can pass around said tube elements in said secondopenings.
 3. A combination as set forth in claim 2 wherein said secondopening is a slot and each slot contains at least two tube elements. 4.A combination as set forth in claim 3 wherein adjacent tube elementshave their first openings directed in opposite directions to provide aclockwise swirling motion in one element and a counterclockwise swirlingmotion in the other.
 5. A combination as set forth in claim 2 whereinthe tube elements are of conStant diameter.
 6. A combination as setforth in claim 2 wherein the first opening along the length of a tubeelement has an area less than the area of the open end of the tubeelement.
 7. A combination as set forth in claim 2 wherein the width ofthe first opening along the length of a tube element is less thanone-quarter of the diameter of the tube element.
 8. A combination as setforth in claim 2 wherein the tube elements have an L/D ratio in therange of 7 to
 25. 9. A combination as set forth in claim 2 wherein saidbody includes radially disposed spray bars with each spray bar having aplurality of holes located along its length, and said means fordirecting a gas propellant flow directs said flow between said spraybars to a position between said body and said face plate.
 10. Aninjector assembly for injecting two propellants into a combustionchamber, one propellant being a liquid, the other propellant being agas, said injector assembly having a body on which there are located aplurality of holes, a tube element being positioned in each hole, saidtube element having an open end and a closed end, each of said tubeelements having two openings therein along its length, one of saidopenings being located adjacent the closed end of the tube element, saidone opening being located at an angle to the radius of the tube elementto provide a swirling effect, the second of said openings being locatedbetween said one opening and the open end of the tube element, saidsecond opening being located at an angle to the radius of the tubeelement to provide a swirling effect, a face plate spaced from saidbody, said face plate having third openings therein, said tube elementsextending into said third openings, said third openings being spacedfrom said tube elements to permit a flow of gas therearound, means fordirecting a primary liquid flow to said second opening of the tubeelements, means for directing a secondary liquid flow to said oneopening of the tube elements, and means for directing a gas flow betweensaid body and said face plate so that it can pass around said tubeelements in said third openings.
 11. A combination as set forth in claim10 wherein said second opening is a slot and each slot contains at leasttwo tube elements.
 12. A combination as set forth in claim 11 whereinadjacent tube elements have their first openings directed in oppositedirections to provide a clockwise swirling motion in one element and acounterclockwise swirling motion in the other.
 13. A combination as setforth in claim 10 wherein the first opening along the length of a tubeelement has an area less than the area of the open end of the tubeelement.
 14. A combination as set forth in claim 10 wherein the width ofthe first opening along the length of a tube element is less thanone-quarter of the diameter of the tube element.
 15. A combination asset forth in claim 10 wherein the tube elements are of constantdiameter.
 16. A combination as set forth in claim 10 wherein the tubeelements have an L/D ratio in the range of 7 to
 25. 17. A combination asset forth in claim 10 wherein the adjacent tube elements are spacedapart and from their cooperating third opening by the relationship A12A2 where A1 and A2 are the areas as shown in FIG.
 6. 18. An injectorassembly for injecting two propellants into a combustion chamber, onepropellant being a liquid, the other propellant being a gas, saidinjector assembly having a body, said body having radially disposedspray bars, each spray bar having a plurality of holes located along itslength, a tube element being positioned in each hole, said tube havingan open end and a closed end, each of said tube elements having twoopenings therein along its length, one of said openings being locatedadjacent the closed end of the tube element, said one opening beinglocated at an angle to the radius of the tube element to provide aswirLing effect, the second of said openings being located between saidone opening and the open end of the tube element, said second openingbeing located at an angle to the radius of the tube element to provide aswirling effect, a face plate spaced from said body, said face platehaving third openings therein, said tube elements extending into saidthird openings, said third openings being spaced from said tube elementsto permit a flow of gas therearound, means for directing a primaryliquid flow through said spray bars to said second opening of the tubeelements, means for directing a secondary liquid flow through said spraybars to said one opening of the tube elements, and means for directing agas flow between said spray bars to said face plate so that it can passaround said tube elements in said third openings.